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BCode: Track the exact types on the stack, rather than only the height.
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@sjrd
sjrd committed Sep 30, 2023
1 parent 8020677 commit a82248f
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Showing 2 changed files with 115 additions and 54 deletions.
113 changes: 62 additions & 51 deletions compiler/src/dotty/tools/backend/jvm/BCodeBodyBuilder.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -79,14 +79,14 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {

tree match {
case Assign(lhs @ DesugaredSelect(qual, _), rhs) =>
val savedStackHeight = stackHeight
val savedStackSize = stack.recordSize()
val isStatic = lhs.symbol.isStaticMember
if (!isStatic) {
genLoadQualifier(lhs)
stackHeight += 1
val qualTK = genLoad(qual)
stack.push(qualTK)
}
genLoad(rhs, symInfoTK(lhs.symbol))
stackHeight = savedStackHeight
stack.restoreSize(savedStackSize)
lineNumber(tree)
// receiverClass is used in the bytecode to access the field. using sym.owner may lead to IllegalAccessError
val receiverClass = qual.tpe.typeSymbol
Expand Down Expand Up @@ -150,9 +150,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
}

genLoad(larg, resKind)
stackHeight += resKind.size
stack.push(resKind)
genLoad(rarg, if (isShift) INT else resKind)
stackHeight -= resKind.size
stack.pop()

(code: @switch) match {
case ADD => bc add resKind
Expand Down Expand Up @@ -189,19 +189,19 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
if (isArrayGet(code)) {
// load argument on stack
assert(args.length == 1, s"Too many arguments for array get operation: $tree");
stackHeight += 1
stack.push(k)
genLoad(args.head, INT)
stackHeight -= 1
stack.pop()
generatedType = k.asArrayBType.componentType
bc.aload(elementType)
}
else if (isArraySet(code)) {
val List(a1, a2) = args
stackHeight += 1
stack.push(k)
genLoad(a1, INT)
stackHeight += 1
stack.push(INT)
genLoad(a2)
stackHeight -= 2
stack.pop(2)
generatedType = UNIT
bc.astore(elementType)
} else {
Expand Down Expand Up @@ -235,7 +235,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
val resKind = if (hasUnitBranch) UNIT else tpeTK(tree)

val postIf = new asm.Label
genLoadTo(thenp, resKind, LoadDestination.Jump(postIf, stackHeight))
genLoadTo(thenp, resKind, LoadDestination.Jump(postIf, stack.recordSize()))
markProgramPoint(failure)
genLoadTo(elsep, resKind, LoadDestination.FallThrough)
markProgramPoint(postIf)
Expand Down Expand Up @@ -294,8 +294,10 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
)
}

def genLoad(tree: Tree): Unit = {
genLoad(tree, tpeTK(tree))
def genLoad(tree: Tree): BType = {
val generatedType = tpeTK(tree)
genLoad(tree, generatedType)
generatedType
}

/* Generate code for trees that produce values on the stack */
Expand Down Expand Up @@ -364,6 +366,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
case t @ Ident(_) => (t, Nil)
}

val savedStackSize = stack.recordSize()
if (!fun.symbol.isStaticMember) {
// load receiver of non-static implementation of lambda

Expand All @@ -372,10 +375,12 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
// AbstractValidatingLambdaMetafactory.validateMetafactoryArgs

val DesugaredSelect(prefix, _) = fun: @unchecked
genLoad(prefix)
val prefixTK = genLoad(prefix)
stack.push(prefixTK)
}

genLoadArguments(env, fun.symbol.info.firstParamTypes map toTypeKind)
stack.restoreSize(savedStackSize)
generatedType = genInvokeDynamicLambda(NoSymbol, fun.symbol, env.size, functionalInterface)

case app @ Apply(_, _) =>
Expand Down Expand Up @@ -494,9 +499,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
dest match
case LoadDestination.FallThrough =>
()
case LoadDestination.Jump(label, targetStackHeight) =>
if targetStackHeight < stackHeight then
val stackDiff = stackHeight - targetStackHeight
case LoadDestination.Jump(label, targetStackSize) =>
val stackDiff = stack.heightDiffWrt(targetStackSize)
if stackDiff != 0 then
if expectedType == UNIT then
bc dropMany stackDiff
else
Expand Down Expand Up @@ -599,7 +604,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
if dest == LoadDestination.FallThrough then
val resKind = tpeTK(tree)
val jumpTarget = new asm.Label
registerJumpDest(labelSym, resKind, LoadDestination.Jump(jumpTarget, stackHeight))
registerJumpDest(labelSym, resKind, LoadDestination.Jump(jumpTarget, stack.recordSize()))
genLoad(expr, resKind)
markProgramPoint(jumpTarget)
resKind
Expand Down Expand Up @@ -657,7 +662,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
markProgramPoint(loop)

if isInfinite then
val dest = LoadDestination.Jump(loop, stackHeight)
val dest = LoadDestination.Jump(loop, stack.recordSize())
genLoadTo(body, UNIT, dest)
dest
else
Expand All @@ -672,7 +677,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
val failure = new asm.Label
genCond(cond, success, failure, targetIfNoJump = success)
markProgramPoint(success)
genLoadTo(body, UNIT, LoadDestination.Jump(loop, stackHeight))
genLoadTo(body, UNIT, LoadDestination.Jump(loop, stack.recordSize()))
markProgramPoint(failure)
end match
LoadDestination.FallThrough
Expand Down Expand Up @@ -765,10 +770,10 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
// on the stack (contrary to what the type in the AST says).

// scala/bug#10290: qual can be `this.$outer()` (not just `this`), so we call genLoad (not just ALOAD_0)
genLoad(superQual)
stackHeight += 1
val superQualTK = genLoad(superQual)
stack.push(superQualTK)
genLoadArguments(args, paramTKs(app))
stackHeight -= 1
stack.pop()
generatedType = genCallMethod(fun.symbol, InvokeStyle.Super, app.span)

// 'new' constructor call: Note: since constructors are
Expand All @@ -790,9 +795,10 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
assert(classBTypeFromSymbol(ctor.owner) == rt, s"Symbol ${ctor.owner.showFullName} is different from $rt")
mnode.visitTypeInsn(asm.Opcodes.NEW, rt.internalName)
bc dup generatedType
stackHeight += 2
stack.push(rt)
stack.push(rt)
genLoadArguments(args, paramTKs(app))
stackHeight -= 2
stack.pop(2)
genCallMethod(ctor, InvokeStyle.Special, app.span)

case _ =>
Expand Down Expand Up @@ -825,12 +831,11 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
else if (app.hasAttachment(BCodeHelpers.UseInvokeSpecial)) InvokeStyle.Special
else InvokeStyle.Virtual

val savedStackHeight = stackHeight
val savedStackSize = stack.recordSize()
if invokeStyle.hasInstance then
genLoadQualifier(fun)
stackHeight += 1
stack.push(genLoadQualifier(fun))
genLoadArguments(args, paramTKs(app))
stackHeight = savedStackHeight
stack.restoreSize(savedStackSize)

val DesugaredSelect(qual, name) = fun: @unchecked // fun is a Select, also checked in genLoadQualifier
val isArrayClone = name == nme.clone_ && qual.tpe.widen.isInstanceOf[JavaArrayType]
Expand Down Expand Up @@ -888,7 +893,10 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
bc iconst elems.length
bc newarray elmKind

stackHeight += 3 // during the genLoad below, there is the result, its dup, and the index
// during the genLoad below, there is the result, its dup, and the index
stack.push(generatedType)
stack.push(generatedType)
stack.push(INT)

var i = 0
var rest = elems
Expand All @@ -901,7 +909,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
i = i + 1
}

stackHeight -= 3
stack.pop(3)

generatedType
}
Expand All @@ -917,7 +925,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
val (generatedType, postMatch, postMatchDest) =
if dest == LoadDestination.FallThrough then
val postMatch = new asm.Label
(tpeTK(tree), postMatch, LoadDestination.Jump(postMatch, stackHeight))
(tpeTK(tree), postMatch, LoadDestination.Jump(postMatch, stack.recordSize()))
else
(expectedType, null, dest)

Expand Down Expand Up @@ -1179,7 +1187,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
}

/* Emit code to Load the qualifier of `tree` on top of the stack. */
def genLoadQualifier(tree: Tree): Unit = {
def genLoadQualifier(tree: Tree): BType = {
lineNumber(tree)
tree match {
case DesugaredSelect(qualifier, _) => genLoad(qualifier)
Expand All @@ -1188,6 +1196,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
case Some(sel) => genLoadQualifier(sel)
case None =>
assert(t.symbol.owner == this.claszSymbol)
UNIT
}
case _ => abort(s"Unknown qualifier $tree")
}
Expand All @@ -1200,14 +1209,14 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
btpes match
case btpe :: btpes1 =>
genLoad(arg, btpe)
stackHeight += btpe.size
stack.push(btpe)
loop(args1, btpes1)
case _ =>
case _ =>

val savedStackHeight = stackHeight
val savedStackSize = stack.recordSize()
loop(args, btpes)
stackHeight = savedStackHeight
stack.restoreSize(savedStackSize)
end genLoadArguments

def genLoadModule(tree: Tree): BType = {
Expand Down Expand Up @@ -1307,13 +1316,13 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
}.sum
bc.genNewStringBuilder(approxBuilderSize)

stackHeight += 1 // during the genLoad below, there is a reference to the StringBuilder on the stack
stack.push(jlStringBuilderRef) // during the genLoad below, there is a reference to the StringBuilder on the stack
for (elem <- concatArguments) {
val elemType = tpeTK(elem)
genLoad(elem, elemType)
bc.genStringBuilderAppend(elemType)
}
stackHeight -= 1
stack.pop()

bc.genStringBuilderEnd
} else {
Expand All @@ -1331,15 +1340,17 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
var totalArgSlots = 0
var countConcats = 1 // ie. 1 + how many times we spilled

val savedStackHeight = stackHeight
val savedStackSize = stack.recordSize()

for (elem <- concatArguments) {
val tpe = tpeTK(elem)
val elemSlots = tpe.size

// Unlikely spill case
if (totalArgSlots + elemSlots >= MaxIndySlots) {
stackHeight = savedStackHeight + countConcats
stack.restoreSize(savedStackSize)
for _ <- 0 until countConcats do
stack.push(StringRef)
bc.genIndyStringConcat(recipe.toString, argTypes.result(), constVals.result())
countConcats += 1
totalArgSlots = 0
Expand All @@ -1364,10 +1375,10 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
val tpe = tpeTK(elem)
argTypes += tpe.toASMType
genLoad(elem, tpe)
stackHeight += 1
stack.push(tpe)
}
}
stackHeight = savedStackHeight
stack.restoreSize(savedStackSize)
bc.genIndyStringConcat(recipe.toString, argTypes.result(), constVals.result())

// If we spilled, generate one final concat
Expand Down Expand Up @@ -1562,9 +1573,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
} else {
val tk = tpeTK(l).maxType(tpeTK(r))
genLoad(l, tk)
stackHeight += tk.size
stack.push(tk)
genLoad(r, tk)
stackHeight -= tk.size
stack.pop()
genCJUMP(success, failure, op, tk, targetIfNoJump)
}
}
Expand Down Expand Up @@ -1679,9 +1690,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
}

genLoad(l, ObjectRef)
stackHeight += 1
stack.push(ObjectRef)
genLoad(r, ObjectRef)
stackHeight -= 1
stack.pop()
genCallMethod(equalsMethod, InvokeStyle.Static)
genCZJUMP(success, failure, Primitives.NE, BOOL, targetIfNoJump)
}
Expand All @@ -1697,9 +1708,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
} else if (isNonNullExpr(l)) {
// SI-7852 Avoid null check if L is statically non-null.
genLoad(l, ObjectRef)
stackHeight += 1
stack.push(ObjectRef)
genLoad(r, ObjectRef)
stackHeight -= 1
stack.pop()
genCallMethod(defn.Any_equals, InvokeStyle.Virtual)
genCZJUMP(success, failure, Primitives.NE, BOOL, targetIfNoJump)
} else {
Expand All @@ -1709,9 +1720,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
val lNonNull = new asm.Label

genLoad(l, ObjectRef)
stackHeight += 1
stack.push(ObjectRef)
genLoad(r, ObjectRef)
stackHeight -= 1
stack.pop()
locals.store(eqEqTempLocal)
bc dup ObjectRef
genCZJUMP(lNull, lNonNull, Primitives.EQ, ObjectRef, targetIfNoJump = lNull)
Expand Down
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